I have a third party huawei phone 7950 which i need to integrate with CUCM, need help with extension  mobility not working .  Any one can help ?

Phone keep registering on display when connected. Current situation : Phone is removed from network , but in CUCM (version: 9.1.2.15900-7) still showing in Rejected state with IP (IP is not reachable as not connected in network) not showing in unknow...